1. Field of the Invention
The present invention relates to a high speed liquid chromatography, and more particularly to a fractionating apparatus for fractionating an effluent solution from a high speed liquid chromatography by dropping the effluent solution on a micro plate or sample plate.
2. Description of the Related Art
In the field of a proteome analysis for elucidating the structure or action of protein or peptide, MALDI-TOF-MS (matrix assisted laser desorption ionisation time of flight) has been noted recently.
MALDI-TOF-MS is the method for making the mass spectrometry by adding a matrix to a biosample and applying a laser beam thereto to ionize the sample. The amount of sample used here is as small as several μL.
In this case, a pretreatment is performed to prepare the sample in an analyzable state. One of the pretreatment methods involves separating or fractionating peptide employing a high speed liquid chromatography, and adding a matrix solution.
Since the biosample is valuable, and the maximum sample amount for allowing the analysis by MALDI-TOF-MS is as small as several μL, the flow rate range usable for the high speed liquid chromatography is several μL/min or less, or preferably 1 μL/min or less.
In fractionating the effluent solution in the normal flow rate range for the high speed liquid chromatography, a fraction collector with an electromagnetic valve is usually employed because the flow rate is large. However, in the micro high speed liquid chromatography for a minute flow rate range, because the electromagnetic valve can not be employed, a method is taken in which in fractionating and collecting the effluent solution, the probe at the final exit is disposed above an object spot such as MALDI plate or MTP (micro titer plate), the plate is made approach the probe, and the operation waits until the effluent solution makes contact with the plate to stick or drop onto the object spot of the plate.
In the method for waiting until the effluent solution sticks or drops, when the constituent of the effluent solution is the liquid having a large surface tension, the effluent solution is greatly swollen like liquid droplet at the distal end portion of the probe on the exit side and sticks thereto, making it difficult to perform the fine adjustment of the effluent solution to be fractionated on the plate.